Fans always running at full speed

I have 2 Cooler Master R4 fans cooling my dual 120mm radiator at the top of my case. One of these is connected to the CPU fan header on the motherboard while the other one is connected to the pwr_fan header (since I have no more fan headers left). However, both of these fans are running at 1,800+ RPM (they are rated for 2,000rpm) even when the system is idle. I have tried going into the BIOS to change the fan speeds but the ASUS Qfan control does not seem to have any options for this. SpeedFan also only works for my rear chassis case and not my rad fans for some reason. Is there any way to make these fans run at a slower or quieter setting?
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More about fans running full speed
  1. The Cooler Master R4 fans have a 3 pin connector, hence their fan speed cannot be controlled via Motherboard/BIOS.
    You'd have to invest in a fan controller.
  2. I thought that 3 pin fans can still be controlled by limiting the voltage that they receive while 4 pin fans use PWM control.
  3. AFAIK, only PWM fans can be controlled through BIOS.
  4. Then how come my R4 fan that I use to exhaust air out the back of my case can be controlled through SpeedFan?
  5. The Pwr Fan connector is designed for the PSU, it cannot be controlled with Q-fan.(not sure about Speedfan) As for the CPU fan header, it should work as long as you've connected the fan correctly.
    http://www.allpinouts.org/index.php/Motherboard_%28CPU%29_4_Pin_Fan
  6. I can only control my rear fan with SpeedFan, none of the other fans respond to it.
  7. So if I disable BIOS fan control, SpeedFan will work for all the fans?
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